Hypodermic syringe



March 23, 1954 D. M. ASHKENAZ HYPODERMIC SYRINGE Filed Oct. 51, 1951 INVENTOR. 1741710 11 flSl/ZKMZ h wl-r L04 [I TTOIPNEY Patented Mar. 23, 1954 by mesne assignments; to American Home Products Corporation, NewYrk, N.'Y., a cornotation of Delaware Application October 31, 1951, Serial No. 254,015

This invention relates to an improved hypodermic syringe, an improved needle therefor, and their combination.

In recent years a type of hypodermic syringe has come into extensive use in which a cartridge of sterile injectable material is placed in the syringe, one end of the cartride is pierced by a sterile double-pointed needle, commonly called in the art a double-cannula needle, which is screwed on a nipple at the end of the syringe, and a movable plug at the end of the cartridge remote from the needle is forced toward the in-' jectable material by pressing on the thumb piece of the syringe plunger.

In the past it has been customary to provide the syringe with a nipple having a small bore and an external or male thread, and to provide the needle with a hub having an internal or female thread. One disadvantage that has resulted from this construction is that the bore of the nipple is necessarily quite small and provides relatively little clearance around the syringe end of the needle. Accordingly it is not easy to insert the sterile needle into a syringe without risk of contacting the needle with the bore of the nipple. Consequently it is necessary that a syringe of this type be sterilized before use to prevent contamination of the sterile needle. The end of the cartridge which is pierced by the needle also requires sterilizing (as by wiping with alcohol) before use. The needle is ordinarily inserted in the syringe first, then the cartridge, and. the syringe plunger is brought to bear on the movable plug in the cartridge, preparatory to injection.

An additional disadvantage is that the small size of the bore in the nipple makes cleaning uncertain, difiicult and time-consuming.

It is the object of my present invention to provide a device which avoids these difliculties.

According to my invention I provide a syringe having a nipple at the needle end which has a considerably increased diameter and a relatively large bore provided with an internal or female thread, and I provide a. double-cannula needle having a hub with an external or male thread; furthermore I provide the hub of my improved needle with an internal or female thread so that it may also fit the conventional type of syringe nipple, thus avoiding the necessity of providing two different types of needle where different types of syringes are sold or used. The provision of two such threads is made possible by the increased diameter of the hub, as compared with conventional needles, which in turn is made pos- 1131mm. (o1. 12s-'-21s) sible by the greater diameter of the syringe'nipple of my invention.

This construction eliminates the need for sterilization of the syringe before use, since the large bore in the nipple permits insertion of the sterile needle without danger of contact with the bore of the nipple and consequent contamination.

My invention is illustrated in the accompanying drawing, but this drawing is intended to be exemplary only and not to limit my invention, the scope of which is defined in the following claim.

In the drawing Fig. 1 represents an assembly of my improved syringe and improved needle, partially in section.

Fig. 2 represents my improved needle, in section.

Fig. 3 is an enlarged sectional view of the nipple end of my improved syringe.

Fig. 4 is an enlarged sectiona1 view of the nipple end of a conventional syringe.

In the drawing a double-cannula needle shaft lis mounted in an improved hub 2. This hub is provided with a knurled portion 3 to facilitate screwing it into the body of the syringe. The hub has a hollow bore 4 which at one end has a diameter approximately equal to the outside diameter of the needle and at the other end is of considerably greater diameter. The end 5 of the hub, surrounding the wider part of the bore, is provided with an external male thread 6, and the wide portion of the bore is also threaded internally with female thread The body of my improved syringe 8 is provided with a large cylindrical bore 9 in which cartridge in is inserted. At one end it is provided with a slideable plunger on rod H, to which thumb piece I2 is aflixed at the outer end. The plunger at the other end of rod ll bears on movable plug I3 of the cartridge. The cartridge is provided at the needle end with a pierceable rubber plug 14. The nipple I5 is integral with the body of my syringe and constitutes its needle end; this nipple is provided with an internal or female thread iii of the same size and pitch as male thread 6 on the hub of the needle. Shoulder 22 is provided at the inner end of thread It to receive the thrust of cartridge I0 during injection. It will be seen from the drawing that bore ll of the nipple of my improved syringe is of relatively large diameter in comparison with the outside diameter of the needle, and readily permits the insertion of the syringe end l8 of needle I without risk of contact with the interior wall of the nipple.

My improved syringe is made of a rigid, dimensionally stable material such as, for exampartially ple, nickelor chromium-plated brass, or a rigid plastic material, which may be turned, drawn, stamped, molded or otherwise fabricated.

In Fig. 4 the needle end of a conventional syringe is shown having nipple I9 provided with an external male thread 20 and a. smooth internal bore Z1. My improved needle will fit such a ppl f mal thread 1 of the neeidl en a in male thread 20 of the syringe, both having the same size and pitch. However, it will be seen that it is much more diiiicult to insert the needle in the conventional syringe without contact with the inner Wall of the nipple. ,Aflcordinglyjnmy improved syringe the risk of infecting ,or,.c ontaminating the needle is substantiallyzeliminated.

I claim:

A double-pointed injection needle adapted .to be mounted in a syringe "barrel by means of a rigid threaded hub constituting an inteeralmart of the needle, said hub having a bore which at one ,end of ,the hub is substantially lar er ,in v1diameter than the needle and .at {the other end Lot 4 the hub is of substantially the same diameter as the outside diameter of the needle, the needle passing centrally through the bore, being firmly fixed therein in the small end of the bore and projecting beyond the hub at each end, the larger end of the bore being provided with an internal female thread, ,said hub ,bein [provided with a knurledicentrall portionaand at tJhB'GIIdSSHIIOUIIding the wider portion of the bore being provided :with an exterior male thread concentric with the interior female thread.

DAVID M. ASHKENAZ.

References Cited in the file of this patent STATES PATENTS 

